Fix prepublish script

package.json

@@ -51,6 +51,7 @@
     "build:test": "tsc --project test/src && webpack --config test/webpack.conf.js",
     "build": "npm run build:src && npm run build:test",
     "docs": "typedoc --options scripts/tdoptions.json",
+    "prepublish": "npm run build",
     "postinstall": "npm dedupe",
     "test:chrome": "karma start --browsers=Chrome test/karma.conf.js",
     "test:coverage": "webpack --config test/webpack-cov.conf.js && karma start test/karma-cov.conf.js",